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freebsd/usr.bin/last/last.c
David Greenman c83d3f4574 Fixed a bug that caused last(1) to be extremely slow in some cases, and
made other performance improving changes. This improves the performance
of last(1) by as much as 32 times in some cases, and in more typical cases
is about twice as fast.
Added a BUGS section to the manual page to describe the behavior of last(1)
when a login shell terminates abnormally (and thus doesn't write a logout
record to the wtmp file).
1995-10-17 18:26:43 +00:00

415 lines
10 KiB
C

/*
* Copyright (c) 1987, 1993, 1994
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef lint
static char copyright[] =
"@(#) Copyright (c) 1987, 1993, 1994\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#ifndef lint
static char sccsid[] = "@(#)last.c 8.2 (Berkeley) 4/2/94";
#endif /* not lint */
#include <sys/param.h>
#include <sys/stat.h>
#include <err.h>
#include <fcntl.h>
#include <paths.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <utmp.h>
#include <sys/queue.h>
#define NO 0 /* false/no */
#define YES 1 /* true/yes */
static struct utmp buf[1024]; /* utmp read buffer */
typedef struct arg {
char *name; /* argument */
#define HOST_TYPE -2
#define TTY_TYPE -3
#define USER_TYPE -4
int type; /* type of arg */
struct arg *next; /* linked list pointer */
} ARG;
ARG *arglist; /* head of linked list */
LIST_HEAD(ttylisthead, ttytab) ttylist;
struct ttytab {
long logout; /* log out time */
char tty[UT_LINESIZE + 1]; /* terminal name */
LIST_ENTRY(ttytab) list;
};
static long currentout, /* current logout value */
maxrec; /* records to display */
static char *file = _PATH_WTMP; /* wtmp file */
void addarg __P((int, char *));
void hostconv __P((char *));
void onintr __P((int));
char *ttyconv __P((char *));
int want __P((struct utmp *));
void wtmp __P((void));
int
main(argc, argv)
int argc;
char *argv[];
{
extern int optind;
extern char *optarg;
int ch;
char *p;
maxrec = -1;
while ((ch = getopt(argc, argv, "0123456789f:h:t:")) != EOF)
switch (ch) {
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
/*
* kludge: last was originally designed to take
* a number after a dash.
*/
if (maxrec == -1) {
p = argv[optind - 1];
if (p[0] == '-' && p[1] == ch && !p[2])
maxrec = atol(++p);
else
maxrec = atol(argv[optind] + 1);
if (!maxrec)
exit(0);
}
break;
case 'f':
file = optarg;
break;
case 'h':
hostconv(optarg);
addarg(HOST_TYPE, optarg);
break;
case 't':
addarg(TTY_TYPE, ttyconv(optarg));
break;
case '?':
default:
(void)fprintf(stderr,
"usage: last [-#] [-f file] [-t tty] [-h hostname] [user ...]\n");
exit(1);
}
if (argc) {
setlinebuf(stdout);
for (argv += optind; *argv; ++argv) {
#define COMPATIBILITY
#ifdef COMPATIBILITY
/* code to allow "last p5" to work */
addarg(TTY_TYPE, ttyconv(*argv));
#endif
addarg(USER_TYPE, *argv);
}
}
wtmp();
exit(0);
}
/*
* wtmp --
* read through the wtmp file
*/
void
wtmp()
{
struct utmp *bp; /* current structure */
struct ttytab *tt; /* ttylist entry */
struct stat stb; /* stat of file for size */
long bl, delta; /* time difference */
int bytes, wfd;
char *ct, *crmsg;
LIST_INIT(&ttylist);
if ((wfd = open(file, O_RDONLY, 0)) < 0 || fstat(wfd, &stb) == -1)
err(1, "%s", file);
bl = (stb.st_size + sizeof(buf) - 1) / sizeof(buf);
(void)time(&buf[0].ut_time);
(void)signal(SIGINT, onintr);
(void)signal(SIGQUIT, onintr);
while (--bl >= 0) {
if (lseek(wfd, (off_t)(bl * sizeof(buf)), L_SET) == -1 ||
(bytes = read(wfd, buf, sizeof(buf))) == -1)
err(1, "%s", file);
for (bp = &buf[bytes / sizeof(buf[0]) - 1]; bp >= buf; --bp) {
/*
* if the terminal line is '~', the machine stopped.
* see utmp(5) for more info.
*/
if (bp->ut_line[0] == '~' && !bp->ut_line[1]) {
/* everybody just logged out */
for (tt = ttylist.lh_first; tt; tt = tt->list.le_next) {
LIST_REMOVE(tt, list);
free(tt);
}
currentout = -bp->ut_time;
crmsg = strncmp(bp->ut_name, "shutdown",
UT_NAMESIZE) ? "crash" : "shutdown";
if (want(bp)) {
ct = ctime(&bp->ut_time);
printf("%-*.*s %-*.*s %-*.*s %10.10s %5.5s \n",
UT_NAMESIZE, UT_NAMESIZE,
bp->ut_name, UT_LINESIZE,
UT_LINESIZE, bp->ut_line,
UT_HOSTSIZE, UT_HOSTSIZE,
bp->ut_host, ct, ct + 11);
if (maxrec != -1 && !--maxrec)
return;
}
continue;
}
/*
* if the line is '{' or '|', date got set; see
* utmp(5) for more info.
*/
if ((bp->ut_line[0] == '{' || bp->ut_line[0] == '|')
&& !bp->ut_line[1]) {
if (want(bp)) {
ct = ctime(&bp->ut_time);
printf("%-*.*s %-*.*s %-*.*s %10.10s %5.5s \n",
UT_NAMESIZE, UT_NAMESIZE, bp->ut_name,
UT_LINESIZE, UT_LINESIZE, bp->ut_line,
UT_HOSTSIZE, UT_HOSTSIZE, bp->ut_host,
ct, ct + 11);
if (maxrec && !--maxrec)
return;
}
continue;
}
if (bp->ut_name[0] == '\0' || want(bp)) {
/* find associated tty */
for (tt = ttylist.lh_first; ; tt = tt->list.le_next) {
if (tt == NULL) {
/* add new one */
tt = malloc(sizeof(struct ttytab));
if (tt == NULL)
err(1, "malloc failure");
tt->logout = currentout;
strncpy(tt->tty, bp->ut_line, UT_LINESIZE);
LIST_INSERT_HEAD(&ttylist, tt, list);
break;
}
if (!strncmp(tt->tty, bp->ut_line, UT_LINESIZE))
break;
}
if (bp->ut_name[0]) {
/*
* when uucp and ftp log in over a network, the entry in
* the utmp file is the name plus their process id. See
* etc/ftpd.c and usr.bin/uucp/uucpd.c for more information.
*/
if (!strncmp(bp->ut_line, "ftp", sizeof("ftp") - 1))
bp->ut_line[3] = '\0';
else if (!strncmp(bp->ut_line, "uucp", sizeof("uucp") - 1))
bp->ut_line[4] = '\0';
ct = ctime(&bp->ut_time);
printf("%-*.*s %-*.*s %-*.*s %10.10s %5.5s ",
UT_NAMESIZE, UT_NAMESIZE, bp->ut_name,
UT_LINESIZE, UT_LINESIZE, bp->ut_line,
UT_HOSTSIZE, UT_HOSTSIZE, bp->ut_host,
ct, ct + 11);
if (!tt->logout)
puts(" still logged in");
else {
if (tt->logout < 0) {
tt->logout = -tt->logout;
printf("- %s", crmsg);
}
else
printf("- %5.5s",
ctime(&tt->logout)+11);
delta = tt->logout - bp->ut_time;
if (delta < 86400)
printf(" (%5.5s)\n",
asctime(gmtime(&delta))+11);
else
printf(" (%ld+%5.5s)\n",
delta / 86400,
asctime(gmtime(&delta))+11);
}
LIST_REMOVE(tt, list);
free(tt);
if (maxrec != -1 && !--maxrec)
return;
} else {
tt->logout = bp->ut_time;
}
}
}
}
ct = ctime(&buf[0].ut_time);
printf("\nwtmp begins %10.10s %5.5s \n", ct, ct + 11);
}
/*
* want --
* see if want this entry
*/
int
want(bp)
struct utmp *bp;
{
ARG *step;
if (!arglist)
return (YES);
for (step = arglist; step; step = step->next)
switch(step->type) {
case HOST_TYPE:
if (!strncasecmp(step->name, bp->ut_host, UT_HOSTSIZE))
return (YES);
break;
case TTY_TYPE:
if (!strncmp(step->name, bp->ut_line, UT_LINESIZE))
return (YES);
break;
case USER_TYPE:
if (!strncmp(step->name, bp->ut_name, UT_NAMESIZE))
return (YES);
break;
}
return (NO);
}
/*
* addarg --
* add an entry to a linked list of arguments
*/
void
addarg(type, arg)
int type;
char *arg;
{
ARG *cur;
if (!(cur = (ARG *)malloc((u_int)sizeof(ARG))))
err(1, "malloc failure");
cur->next = arglist;
cur->type = type;
cur->name = arg;
arglist = cur;
}
/*
* hostconv --
* convert the hostname to search pattern; if the supplied host name
* has a domain attached that is the same as the current domain, rip
* off the domain suffix since that's what login(1) does.
*/
void
hostconv(arg)
char *arg;
{
static int first = 1;
static char *hostdot, name[MAXHOSTNAMELEN];
char *argdot;
if (!(argdot = strchr(arg, '.')))
return;
if (first) {
first = 0;
if (gethostname(name, sizeof(name)))
err(1, "gethostname");
hostdot = strchr(name, '.');
}
if (hostdot && !strcasecmp(hostdot, argdot))
*argdot = '\0';
}
/*
* ttyconv --
* convert tty to correct name.
*/
char *
ttyconv(arg)
char *arg;
{
char *mval;
/*
* kludge -- we assume that all tty's end with
* a two character suffix.
*/
if (strlen(arg) == 2) {
/* either 6 for "ttyxx" or 8 for "console" */
if (!(mval = malloc((u_int)8)))
err(1, "malloc failure");
if (!strcmp(arg, "co"))
(void)strcpy(mval, "console");
else {
(void)strcpy(mval, "tty");
(void)strcpy(mval + 3, arg);
}
return (mval);
}
if (!strncmp(arg, _PATH_DEV, sizeof(_PATH_DEV) - 1))
return (arg + 5);
return (arg);
}
/*
* onintr --
* on interrupt, we inform the user how far we've gotten
*/
void
onintr(signo)
int signo;
{
char *ct;
ct = ctime(&buf[0].ut_time);
printf("\ninterrupted %10.10s %5.5s \n", ct, ct + 11);
if (signo == SIGINT)
exit(1);
(void)fflush(stdout); /* fix required for rsh */
}